This invention relates generally to a ring mechanism for retaining loose-leaf pages and more particularly to an improved mechanism for opening and closing ring members and for locking closed ring members together.
A ring mechanism typically retains loose-leaf pages, such as hole-punched papers, in a file or notebook. A pair of hinge plates are supported within a housing in joined relation for loose pivoting motion relative to the housing. The housing is generally narrower than the joined hinge plates when they are in a coplanar position (180°). So as the hinge plates pivot through the coplanar position, they deform the housing and cause a spring force that urges them to pivot either upward or downward. Ring members mounted on the hinge plates move with the pivoting movement of the hinge plates. The ring members open when the hinge plates pivot upward and close when the hinge plates pivot downward.
Some ring mechanisms include structure such as, for example, control slides located between the housings and the hinge plates to lock the ring members together when they close. The control slides engage upper surfaces of the hinge plates and block the hinge plates from pivoting upward when it is desired to hold the closed ring members together. The control slides move to a position allowing the hinge plates to pivot freely when it is desired to open the ring members. These mechanisms can be difficult to make, however, because the control slides are generally installed within the housings before the hinge plates. Consequently, proper positioning of the control slides relative to the hinge plates can be difficult. Additionally, the control slides may have a complex shape to interact with the hinge plates. This can increase production costs of ring mechanisms incorporating these control slides.
Accordingly, it would be desirable to provide a ring mechanism that is easy to make and includes a simplified travel bar.